Aqueous Al-Ion Supercapacitor with V₂O₅ Mesoporous Carbon Electrodes

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Developing high-performance, cost-effective energy storage devices is crucial.
• Aqueous aluminum-ion (Al-ion) supercapacitors offer potential due to aluminum's abundance and trivalent charge.
• Challenges remain in achieving high energy density and long cycle life in Al-ion systems.

Purpose of the Study:

• To fabricate and characterize a high-performance, low-cost, aqueous Al-ion supercapacitor.
• To investigate the energy storage mechanism of nanostructured V2O5 integrated with mesoporous carbon microspheres (MCM/V2O5).
• To evaluate the electrochemical performance, including energy density and cycling stability.

Main Methods:

• Fabrication of MCM/V2O5 composite electrodes.
• Assembly of an aqueous Al-ion supercapacitor using Al2(SO4)3 electrolyte.
• Electrochemical characterization including cyclic voltammetry, galvanostatic charge-discharge, and cycling tests.

Main Results:

• The MCM/V2O5 composite demonstrated well-dispersed nanostructured V2O5 within a mesoporous carbon matrix.
• The supercapacitor exhibited redox behavior attributed to Al3+ intercalation/deintercalation and V5+/V4+ redox reactions.
• Achieved an energy density of 18.0 Wh kg-1 at 147 W kg-1.
• Demonstrated excellent cycling stability with over 88% capacitance retention after 10,000 cycles.

Conclusions:

• The integrated MCM/V2O5 electrode effectively combines electric double-layer capacitance and pseudocapacitance for enhanced performance.
• High-performance aqueous Al-ion supercapacitors are feasible using trivalent Al-ion guest species.
• This research provides new avenues for developing advanced supercapacitor technologies.